The present invention involves an improved chopper for chopping continuous or very long fiber, fiber strands, yarn, string, wire, ribbon, tape and the like comprising a backup roll and a blade roll. More specifically, the present invention involves a chopper having a novel quick release knock off-knock on roll retainer for the rolls that must be frequently changed, and means for tilting the chopper to change the angle of discharge of the chopped strand, etc.
It has long been known how to chop continuous fibers or fiber strands into short lengths of about 3 inches or shorter. More than a billion pounds of such products including chopped glass fibers and fiber strands are produced each year in processes and chopping apparatus like those disclosed in U.S. Pat. Nos. 5,970,837; 4,398,934; 3,508,461; and 3,869,268. The choppers disclosed in these patents comprise a blade roll containing a plurality of spaced-apart blades for separating the fibers into short lengths, a backup roll, frequently driven, which the blades work against to effect the separation and which pulls the fibers or fiber strands, often using an idler roll to hold the fibers or fiber strands down onto the surface of the backup roll. In the chopped fiber processes disclosed in these patents, the chopper is usually the most productivity limiting equipment in the processes that typically operate continuously every day of the year, 24 hours each day. Therefore, improvements in the chopper that allow the chopper to pull and chop faster, allow longer times between maintenance shutdowns, and/or to pull and chop more fibers or fiber strands at a time have an extremely positive impact on productivity and production costs.
Due to wear, the blade roll and backup roll on each chopper must be changed frequently with the actual life between changes depending upon the type of item being chopped. The life typically ranges between 4 and 24 hours or more, but a defect in a blade or the elastomer layer on the backup roll can cause even shorter life. Due to their tightness on their spindles and the tacky chemical sizing from the fiber that gets on all exposed parts, it has been necessary to strike the old blade rolls and old backup rolls with a hammer or a heavy bar to loosen them from their spindles before they could be removed for replacement with new rolls. This hammering damages the rolls and in time knocks them out of alignment causing vibration and premature replacement. These are expensive problems for the industry considering that there are hundreds of fiber choppers in operation.
Another problem with fiber choppers when chopping wet fiber having a tacky chemical sizing on the surface of the fibers is that the stream of fibers will, depending on factors such as moisture content and the degree of tackiness of the sizing, leave the chopper at different angles. This presents a problem in catching the fiber with a conveyor belt due to the limited space in the fiber forming rooms where the fiber is formed and chopped and results in some fiber being thrown off the conveyor and onto the floor causing scrap and a housekeeping problem. This problem is discussed in U.S. Pat. No. 4,161,897 and the problem is addressed in that patent by designing the chopper such that the position of the blade roll can be changed to contact the backup roll in different locations. While this may change the angle of discharge of the chopped fiber, it greatly complicates the design and is a costly solution. A simpler, less costly solution has been needed.
The present invention includes an improved chopper that comprises a backup roll and a blade roll, each roll being mounted on a spindle with a novel fast acting knock off/knock on roll retainer for holding the blade roll and/or the backup roll in place and for pulling the roll(s) loose from its spindle. This roll retainer assembly comprises a spinner attached to a stub shaft at or near one end, the stub shaft having engaging means that will engage with the spindle for the roll, a locking cup surrounding the stub shaft and free to rotate around the stub shaft, the locking cup having a depression therein with an opening facing away from the spinner, a lock-ring or collar surrounding the stub shaft and residing in the depression in the locking cup, the lock-ring being fixed to the stub shaft. The roll retainer also comprises a locking plate attached to the open end of the lock cup, the locking plate having two or more slots therein for allowing heads of shoulder bolts that are fastened to the blade roll and/or backup roll at locations spaced from the axis of the roll to pass into or through the slots in a wide portion of the slots. At least one end portion of each slot is narrower than the heads are wide such that the heads cannot pass through the narrower end portion(s) of the slots.
Preferably the assembly also includes a thrust washer or a lubricated washer around the stub shaft and between the spinner and the lock cup to enhance the tightening and loosening of the spinner. Preferably the roll retainer also comprises a lubricated thrust washer in the bottom of the depression in the lock cup to enhance relative movement under stress between the locking ring and the lock cup. Also, preferably the roll has two or more shoulder bolts circumferentially spaced around the opening, most preferably equidistant from each other and from the axis of the roll. This chopper can also comprise means on or attached to the chopper for lifting one side of the chopper to tilt the chopper to change an angle of discharge of an array of chopped product discharging from the chopper.
The present invention also includes a fast acting roll or wheel retainer comprising:
a) a cylindrical stub shaft having one end portion threaded,
b) a locking ring having a spaced apart parallel surface perpendicular to and surrounding the stub shaft and being either integral with the stub shaft or being rigidly attached to the stub shaft,
c) a spinner having one or more handles, the spinner being located at or near an end of the stub shaft opposite the end that is threaded, the spinner being either integral with the stub shaft or rigidly attached to the stub shaft,
d) a lock cup having a bottom and an open top, the bottom of the locking cup having a hole therein and surrounding the stub shaft in a ratable manner at a location between the two ends of the stub shaft, the open top of the locking cup being closest to the threaded end of the stub shaft, and
e) a locking plate attached to the open end of the lock cup, the locking plate having a hole therethrough for the stub shaft to reside in a rotatable manner, the locking plate having one or more slot openings at least partially therethrough and spaced from the hole for the stub shaft, each slot opening having a wide portion and a narrower portion, one face of the locking plate being compatible with an engaging face on the roll or wheel and the area on an opposite face around the narrower portion of each slot being compatible to engage a bottom surface of an enlarged head of one or more projections extending from an outboard surface of said roll.
The present invention also includes a method of removing a used roll and replacing it with a new or repaired roll, each roll having an opening around its axis and at least two shoulder bolts with enlarged heads spaced from its axis and protruding from a face of the roll, on a chopper, or other apparatus, having a spindle with threads on a working end using a novel knock on/knock off roll retainer assembly that comprises a spinner attached to a stub shaft at or near one end, the stub shaft having engaging means that will engage with the spindle, a lock cup surrounding the stub shaft and free to rotate around the stub shaft, the lock cup having a depression therein with an opening facing away from the spinner, a lock ring or collar surrounding the stub shaft and residing in the depression in the lock cup, the lock ring being fixed to the stub shaft and a locking plate attached to the open end of the lock cup, the locking plate having one or more slots therein for allowing heads of projections fastened to the blade roll and/or backup roll at locations spaced from the axis of the roll to pass through a wide, central portion of each slot, at least one end portion of each slot being narrower than the heads are wide such that the heads cannot pass into or through the narrower end portion(s) of the slots, comprising the steps of:
a) rotating the spinner in a direction to back the stub shaft off a spindle having a threaded portion such that an outer face of the locking plate which is in contact with the enlarged heads of the shoulder bolts will pull the used roll loose from the spindle without damaging the roll,
b) rotating the locking plate such that the wide portion of the slots align with the enlarged heads of the shoulder bolts,
c) rotating the spinner to back the stub shaft off of the spindle while preventing the locking plate from rotating and removing the roll,
d) placing a new or repaired roll onto the spindle such that a portion of the spindle is in the opening of the roll and such that the two or more projections are facing away from the chopper or other apparatus,
e) threading the threaded stub shaft of the roll retainer assembly onto the spindle,
f) aligning the slots in the locking plate so that the wide portion of the slots align with the enlarged heads of the shoulder bolts on the roll,
g) rotating the spinner to move the stub shaft further onto the spindle while maintaining the alignment of the slots as described in (f) above until the lock plate is against a hub of the roll and the roll is snugly in place on the spindle, and then backing off the stub shaft by rotating the spinner in the opposite direction about 5 to about 180 degrees,
h) rotating the locking plate until the end of the slots at the narrower end portion engage the shoulder bolts, and
i) rotating the spinner to move the stub shaft onto the spindle the amount backed off in step (g) and then knocking the spinner or a projection on the spinner to tighten the roll on the spindle.
The present invention also includes a chopper for separating long fiber, fiber strands, string, wire, tape or ribbon into short pieces and discharging the short pieces in a direction away from the chopper, the chopper comprising a blade roll, a backup roll and a frame, the improvement comprising means for varying the elevation of one end of the frame of the chopper for the purpose of changing the angle of discharge of the short pieces from the chopper or for maintaining the angle of discharge the same when a different item is fed into the chopper, i.e. an item which has a different tendency to adhere to the elastomer layer on the backup roll. The means for varying the elevation is preferably a jack screw, but can be any known compact means of lifting including a gas cushion lifting device, a fluid cylinder lifting device, a mechanical lever type lifting device similar to a bumper jack with lock, a chain hoist or winch mounted above the chopper frame, and other equivalent lifting devices or shimming means.
Preferably, the lower side of the chopper opposite the lifting means is pivotly mounted to a foot or feet that is/are bolted to the floor or otherwise equipped so that the feet won""t slide along the floor when the opposite end is raised by the lifting means. The chopper can be any chopper having a backup roll and a blade roll including the improved chopper using the novel roll retainer described above.
The present invention also includes a chopper for chopping items selected from the group consisting of fibers, fiber strand, yarn, string, wire, and ribbon, tape that enter the chopper in an unwound form at a high linear speed into an array of short lengths, the chopper having an upstream side and a downstream side and a blade roll and a backup roll, the improvement comprising: a second framework or an inner frame or member on which the chopper is mounted, the second framework or inner frame or member being pivotly supported near one side of the chopper by a first framework or an outer frame surrounding at least a part of the second framework or inner frame or member, and lifting means attached to an opposite side of the chopper, said opposite side of the chopper being opposite the side that is near where said inner frame is pivotly supported.
The present invention also includes a method of separating long lengths of items such as fiber, fiber strands, string, wire, tape or ribbon into short pieces by passing the items continuously into a nip between a rotating blade roll and a rotating backup roll of a chopper whereby the item is separated into short pieces which are discharged from the chopper in an array having a direction, the improvement comprising changing the elevation of one end of the chopper with respect to an opposite end of the chopper to change the direction of the array of short pieces.
When the word xe2x80x9caboutxe2x80x9d is used herein, it is meant that the amount or condition it modifies can vary some beyond that so long as the advantages of the invention are realized. Practically, there is rarely the time or resources available to very precisely determine the limits of all the parameters of one""s invention because to do so would require an effort far greater than can be justified at the time the invention is being developed to a commercial reality. The skilled artisan understands this and expects that the disclosed results of the invention might extend, at least somewhat, beyond one or more of the limits disclosed. Later, having the benefit of the inventor""s disclosure and understanding the inventive concept and embodiments disclosed, including the best mode known to the inventor, the inventor and others can, without inventive effort, explore beyond the limits disclosed to determine if the invention is realized beyond those limits and, when embodiments are found to be without unexpected characteristics, those embodiments are within the meaning of the term xe2x80x9caboutxe2x80x9d as used herein. It is not difficult for the skilled artisan or others to determine whether such an embodiment is either as might be expected or, because of either a break in the continuity of results or one or more features that are significantly better than reported by the inventor, is surprising and thus an unobvious teaching leading to a further advance in the art.